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Habitats with the highest number of threatened mammals and birds are lowland and mountain tropical rainforest. Freshwater habitats are extremely vulnerable with many threatened fish, reptile, amphibian and invertebrate species. In the last 500 years, because of humans 816 species of animals have been forced into extinction. Many species have been eliminated from areas dominated by human influences. Even in preserves, native species are often out-competed or consumed by organisms introduced from elsewhere. Extinction is a natural process, but it is occurring at an unnaturally rapid rate as a consequence of human activities. Already we have caused the extinction of 5%-20% of the species in many groups of organisms, and current rates of extinction are estimated to be 100-1,000 times greater than pre-human rates.
The Carolina parakeet used to range from Mexico to New York State. It was the only parakeet to adapt successfully to the harsh winters of eastern North America, but because of the destruction of America's woodlands to create farmland, this species of parakeets home was destroyed. These birds were also shot to protect farmers" crops, for a sport, and for their beautiful feathers, which the ladies liked to wear on their hats. Once one of the parakeets was wounded or killed, the other ones would fly around it instead of deserting it, which made it easier for the hunters to pick them off one by one. Cause of this species extinction? Humans destroyed their habitats for the benefits of themselves and killed them for a sport. .
There used to be thousands and thousands of Passenger Pigeons. So much that they were said to be able to uproot a tree when they all landed on it because of the weight of all of them. During the nineteenth century, hundreds of thousand of the birds were sold to the meat markets of New York City. Hunting for sport also affected the number of the species incredibly.
